A Hero's Lost Legacy
by EmeraMist
Summary: AU where Tsunayoshi is the son of the seventh wielder of One for All, Nana Shimura, a forgotten young child. He goes to U.A. as an adopted Sawada, along with a small group of friends, wielding strange and beautiful fire skillfully. He meets a certain person's protege there, Toshinori Yagi. In the end, he really wishes he could've seen how Tenko, now Tomura had grown up.
1. Chapter 1

**I haven't really seen any fanfic crossovers surrounding this as an idea, so if there are any, please do tell me about them. Anyway, I got this shot of inspiration from reading a BNHA fanfic when suddenly the epic 'Tsuna Awakens' OST started playing in YouTube. So I hope you all enjoy! Any OC's mentioned in here won't be important as there wasn't much information about All Might's old classmates**

* * *

 **PROLOGUE: A TWINGE OF FAMILIARITY**

It was when a certain dark-haired beauty walked in on a fight between two students of the prestigious hero high school, U.A., one whom she knew personally and on a level just like a teacher, and one who just struck a chord of familiarity and sadness within her, to her confusion. Shimura Nana had come across these two arguing outside the building when she was just coming over to see a good friend of hers and probably the principal.

"Toshi? What are you doing, fighting and arguing with others?" Nana frowned a bit, his smile was extremely forced and she noted that the other teen was actually holding his own fairly well against her protege, despite being small for his age. Not only did he look small, but he also had very soft and messy brown hair, again, the twinge of familiarity ached within her.

Her sudden appearance apparently stopped the fight as Toshi turned to stare at her with some incredibility and a little, to her approval, shame at being caught in a fight with a fellow student, if the U.A. uniform the other boy was wearing was anything to go about. However, the other boy merely just stepped a little to his left, so that his face was still hidden from her but he was acknowledging her presence.

She was looking at her successor expectantly so it was a surprise to her and Toshi both when the other boy was the one who answered her question before Toshi. His voice, soft and a little weak it may be, but he had an air of confidence when he spoke and an air that certainly commanded the attention of anyone nearby.

"It was nothing really, ma'am, just a small disagreement." the teen spun to face her and Nana could've sworn her heart had just launched itself into her throat and she had stopped breathing because no one could have a face that familiar, similar, to _him_. To the one person she knew she disappointed the most.

This teen looked so much like her deceased husband too, the teen's hair was definitely much more messier than his had been when he was at the teen's age, the shade was also adopted from the deceased man, only darker, a shade of healthy and plain brown, the teen's mouth was set in a way that reminded her of the days when she was a student fighting her would-be lover at the annual Sports Festival.

This teen was notably smaller in size than her deceased lover during his UA years, but the eyes glowed with the exact same intensity and determination, the colour, however, was very much off. Instead of it being an orange shade of his orbs, his eyes blinked and that strange yet mesmerizing sunset-orange eyes had her widen her eyes.

Only one person had those eyes, only _he_ had them.

Then, the teen blinked and his eyes returned to a comfortable brownish-orange colour, making Nana think that she had just imagined them.

"I apologize for causing you trouble, Toshinori-san, and for causing you to worry about him ma'am. Excuse me, but I must take my leave now, see you tomorrow, Toshinori-san, I do hope that you don't bear any grudges because of this." The teen nodded in his direction as he bowed and left the scene, shouldering the bag that was left by the gates and exiting.

"Toshi, who was that and what were you two fighting about?" Nana frowned as she knelt down and touched a burn mark in the shape of a palm on her successor's right arm. "He got you in close range?"

Toshinori winced as his mentor touched the burn mark. "Yeah, well, that's my classmate, and about that disagreement he spoke off..." Toshinori's smile dropped a bit. "It was just a crash of ideals that's all!" And just like that, his smile returned full force, but Nana had seen through him and started to pinch his cheeks.

"Oh really now? Why don't you just tell me?" She pulled them continuously and ignored the protesting sounds he was making. When she released her fingers, her smile sending little shivers down his spine, he massaged his cheeks and looked a little annoyed.

"Ow! That really hurt, Shimura-sensei!" Toshinori winced as he relented. "Okay okay! I'll tell you later, but don't you need to do something since you came here?"

Really, Nana didn't forget about it, she just set it aside so she shook her head. "I can do that tomorrow, it's probably late and they're probably busy. So come on, I'll walk you home and you can tell me all about it along the way." The confusion on her student's face was apparent and she waited for him to ask her the question on his mind, and the question she was expecting.

Toshinori had ignored the first statement as his curious surfaced at the second. "Why can't I go home myself? I'm old enough, what makes today different? And I can always text you about it or tell you tomorrow, Sensei."

Nana stood up as both her and Toshinori walked out of the gates, Nana's staff pass giving her the liberty to walk in and out, even though she technically wasn't a permanent staff. "The villains are brewing and are getting more dangerous," her eyes narrowed. "I don't know whether if All for One is behind it all..."

The air surrounding them grew tense and close to suffocating as Toshinori gulped. "Ah, let's think about that another time! Come on, we can go get some ice cream while you tell me about what happened, alright?"

Toshinori spun his head to meet his teacher's bright smile as he smiled back just as brightly, grateful for her attempt to calm him, he nodded his head.

* * *

"Let's see now, that boy is, for starters, one of my classmates, and is the closed off type. I've never seen him willingly interact with anyone, oh wait! I remember now, there was only one person in our class he would talk to or do anything with." Toshinori snickered at the mention of that person. "It was a girl, she was weird too and OW!"

Nana playfully smacked his arm as she huffed and turned away to hide an amused smirk. "Don't call people weird, especially if you're not really on friendly terms with them and judging by your introduction of her, you aren't."

"Bleh! Anyway, the entire class knows that they've been friends since their childhood and we all suspect that they sometimes share weird things with each other. Oh yeah! I forgot to tell you, his name is Sawada Tsunayoshi, but we call him Sawada or Tsuna for short."

Nana froze and she didn't seem to register that her pupil was looking at her strangely. _Tsuna_?

* * *

 _"Congratulations! What do you want to name him?"_

 _"Yoshi, maybe?"_

 _"Nah, let's add something else in front. Oh! I know! How about Tsunayoshi?"_

 _"That sounds nice, okay then, welcome to the world, Shimura Tsuna."_

 _"It's Shimura Tsunayoshi!"_

 _"But Tsunayoshi is a mouthful!"_

 _"Fine, Shimura 'Tsuna' Tsunayoshi."_

* * *

"Erm... sensei, are you alright? You seem... out of it..." Toshinori waved his hand repeatedly in front of her face. That seemed to snap her out of it and she recovered quick enough to reassure her pupil and successor. She shot him a bright smile.

"No worries Toshi! Haha! With that attitude and worry for others, I know that one day, you'll be a great hero." She ruffled his hair and pointedly ignored his protests.

"So Toshi, tell me more about this classmate of yours, and that girl he interacts with too! They sound pretty interesting and to have injured you of all people in close combat rather severely, my curiosity is certainly piqued! Though I suppose it shouldn't be that surprising, you can't really manage 100% immediately and unconsciously, and you still seem to be having a little bit of trouble controlling and holding back your strength so that you don't accidentally hurt them. And it's funny how you never went to see the quirk specialist when you were young, you can't even activate the quirk without your Body Buff quirk, and believe me, you know that the quirk is especially useless without anything that needs a buff body and..."

Toshi immediately cut off the rant while his teacher had an innocent, a way too innocent smile on her face as his own face flushed. "Alright! Alright I know I have much to improve sensei!"

"Ah? I wasn't saying anything but it seems you have matured~" Toshi half-heartedly glared at his amused teacher. "I mean, all I asked for was about the girl and boy."

 _It's just coincidence..._

"... Sensei, am I that easy to mess with?"

 _Just coincidence..._

"Oh? I mean, that's entirely up to you!"

 _...Right?_

"..."

* * *

 **And that's the end of this prologue! The next chapter will jump back in time before All Might and Tsuna enrolled in UA. And if any of you can guess who is this girl Tsuna is familiar with, please, I want to hear your thoughts before I reveal it in future chapters.**

 **I don't know when I'll be updating, since I really do want to complete TTH and its prequel, but this is a shot of inspiration and I hope I can update the next chapter soon.**

 **I hope you enjoy!**


	2. Chapter 2

**I apologize for any grammar errors. And I also apologize for the long wait, this story was left in the drawer as I was working on the Trinisette Heirs and its prequel. I promise you guys, this story will be updated in the same week as Trinisette Heirs from now on.**

 **And by the way, Chrome may be in the tags I included, but it doesn't mean that Tsuna's permanently paired with her, it could be a temporary thing, or others could mistake that they're together when they treat each other like siblings instead. All it means is that Chrome will be one of Tsuna's biggest supporters no matter what he does, in a girlfriend way or sibling way, take it however you want, after all, it'll be revealed one day,**

 _Lita of Jupiter: Yep, it's Chrome. And about the others, yeah they'll be around, probably this chapter, haha. As for classes, as at least one of the Guardians are quirkless, and UA's hero course doesn't accept quirkless students, yeah, at least one will be in another class. I will include Support Classes, General Studies, Hero Course and Business, probably business anyway. None of them will be alone in a class.  
_

 _Nina: Thank you ^_^  
_

 _Maya: Thank you too!  
_

 _Aiyobi Uzumaki: Yep!_

* * *

 **FOUND IN THE RAIN**

A young brunette boy was left in the nearby orphanage, with zero to no memories of his biological family. All he remembered was the sting of loneliness and betrayal he, as a two-year old, felt. And the cause of it was his own mother, that much he knew. He couldn't remember anything from his past life, so the matron, who was a really nice lady with a barrier quirk, named him Tsunayoshi, after one of the Tokugawa shoguns. The matron of the orphanage stared out of the orphanage window, her sad eyes fixed on the now four-year old child who was sitting against the building's walls.

She thought back to when she had first found him, it was one of the most painful and heartbreaking event to relieve.

* * *

Hotaru Mika was resting in her private room at the orphanage she ran, staring out the window with a book in hand. The rain had gotten extremely heavy and she had made sure the children stayed within the small building. It was a simple life, and a sad one, for most of the children she watched over had difficult abilities, the world dubbed it as 'Quirks', and as they grew older, they tend to use it much more.

The children were mostly rather sociable and cheerful, (there were the obvious exceptions) _little mischievous brats they were_ , she thought fondly and a little irritated, there were those in the group that loved to play pranks on the others. Of course, they all seemed to have fun in the end, but it still was annoying, having to clean up after some messier pranks.

Most of them had ambitions for the future, and most were victims of villain attacks, where their parents had perished in the aftermath, leaving them alone. These children wanted to become heroes, wanted justice for their parents, and those with weaker quirks wanted to work behind the scenes. There were one or two that were children of villains, they were either abandoned here because they were thought of as weak, or that their parents were in jail or had died as well. There were also two particular ones, siblings, a boy and a girl who were treated horribly by their families and escaped, later found by her. The young boy had an eye transplant, but the girl had lost her eye and no suitable replacement could be found.

She closed her book and drew the curtains, ready to go prepare dinner for the children when one of them burst into her room, and anxious look on his face.

"Hotaru-san!" The eldest orphan shouted for her as his panting figure entered her room.

"Takeshi-kun?" Mika hurriedly approach the black-haired boy, who now looked so worried, in deep contrast to his usual carefree self.

"A boy! He's outside, unconscious! I saw an adult figure leave him there in the rain! There's only a blanket and he's really young!" The six-year old child rushed, greedily taking in deep breaths of air each time.

"What! Takeshi, you come with me!" The boy hurriedly nodded and followed the matron as she ran outside. Just as she ran passed the living room where the rest of the children were, she stopped and called out to them.

"Hayato!" She called out to the silver-haired boy who was younger than Takeshi by a little over 4 months. The silver-haired pianist scowled at her, just like he scowls at everyone, but she was used to his personality.

"What?!"

"I need you to get some towels ready! There's a young boy out there and he's probably freezing to death now!" The boy's eyes widened as he quickly ran off, almost knocking her over, and entered the room at the far end of the small flat building.

"Come on Takeshi!" She shouted for the boy to follow her.

Mika and Takeshi reached the unconscious child just as the rain started to become heavier, the matron cursed as Takeshi felt his forehead and shouted to her over the rain that the child had a fever. She picked the child up from the floor and sure enough, his forehead really was hot and the child's breathing was also slightly heavier than an average child. She hoisted him into her arms, it was pretty simple seeing as the child couldn't be more than 2-years-old and he was pretty light and skinny.

"Takeshi, go tell the other kids please! And better yet, prepare some warm chicken soup for this boy!" She was frantic, and it was evident as the two ran head on into the building before going their separate ways, she met up with a determined and concerned Hayato who immediately handed her the towels.

"Shit! He does not look good at all!" Hayato swore, it was one of those times that he really wished that he inherited his late mother's healing quirk. "And I can't do anything about it..." He trailed off.

Mika knew what was going through Hayato's mind the instant he said that last sentence and she flicked her eyes to stare sternly at the boy. "Don't Hayato, don't think of yourself like that!"

"Tch! It's true though! I'm quirkless! All I'm good for is archery and piano! And how do you expect to beat those with accuracy quirks huh?! Tch!" Hayato ran off, Mika staring at the boy's back sadly and with a haunted expression.

"I'll have to find him later on..." she muttered. "But now, let's take care of this child." She ran to her room and placed the unconscious child on the couch.

* * *

"Do you think he's going to be extremely okay?" a white-haired boy asked another child. The children were watching from behind the matron's room doors, looking at the brunette who had yet to make a single motion that would indicate that he was coming back into the land of the living.

"Hn, I don't know..." a black-haired five-year old answered. If one didn't know him beforehand, one would think that he just didn't care, but those who knew him could feel the tint of anxiety underneath his cold demeanor.

"He's around the same age as my dearest little sister..." another noted with a touch of fondness.

"Bah! He could be malnourished!" Hayato walked in on the conversation, keeping his voice down.

"Oya oya? You're back. And can we not think of _that_ possibility?" the five-almost-six-year old boy said with a twitch of his fingers, as if not wanting to relieve something painful.

"Fine... Has he woken up already?" the worried undertone was easy to pick out.

The white-haired five-year old was the one who answered. "No." he changed the subject. "Have the others gone to sleep yet?"

"I think so, its late, we should too. Takeshi is still making the soup." Hayato answered distantly.

"... I'll keep watch." the black haired child said with a tone of finality. Hayato scrutinized his face.

"...Alright. You sure about that? You already don't sleep much." He relented.

"Yes. Go."

"I'll get the kiddo to give me some of her strawberry cake for you then."

"Go!"

The rest of the children ran off snickering to themselves as the black haired child chose to glower and clicked his tongue instead.

* * *

Brownish-orange eyes slowly fluttered open in the room, the owner of the eyes woke to a much different sight than he had expected. A white ceiling, a single ceiling fan that seemed to span across the entire ceiling. Turning his head to the side, he was met with the back of some sort of furniture, huh, that explains the comfort. He turned again, and this time was met with a desk, pale yellow walls, some papers scattered on the floor, two armchairs, another two couches.

 _Where am I? I'm not dead right?_

With those thoughts in mind, he missed the sound of light, swift and agile footsteps racing away, courtesy of one of the orphans here rushing off to inform the matron.

Just as he started to get up, he was then aware that he had no recollection of what had happened. All he remembered, was an adult figure, female no doubt, setting him down on the floor, no! On the ground! The cold, wet, damp ground.

Anything further back, was all a blank. It gave him a headache trying to remember. _Agh! I just woke and already feel horrible!_

 _Am I even alive?_ he thought wistfully with a frown. _I am, right? It would explain why I still have my five senses... Or is this the afterlife?_

"Oh good! You're awake!" A female voice rang from the entrance of the room. _That answers it, I am alive._ "Do you feel fine? Need anything?"

"Ah..." he sat up slowly and would've collapsed onto the soft surface had it not been for the female supporting him.

"Careful there, you just recovered." the woman was kind, he decided, but wondered if it was all just an act to get him to lower his guard. Wait, what had happened? Why was he here? Why did that woman put him on the ground?

"My name is Hotaru Mika, you can just call me Mika-san, or if it makes you uncomfortable, Hotaru-san. And what's your name?" She helped him sit up. He just stared in confusion into her eyes. "What is it?" She asked, seeing his confusion.

"I...I don't remember my name... something about a Tuna?" he scrunched his eyebrows, desperately trying to think, and Mika held back a torrent of choked laughter.

"I think it was Tsuna." She decided, if he doesn't remember anything, she'll name him, like she did to the two siblings here. "How about Tsunayoshi for your name? Would you like it?" She asked him gently. Her many times great-grandfather had relations with the Tokugawa Shogun named Tokugawa Tsunayoshi, why not give the young child the same name?

"Tsuna... yoshi?" What was happening now? Oh right, he doesn't remember his original name, does he? No no, so the woman, uh... Hotaru-san was giving him one? It sounded like a pretty nice name.

"Yes, it's the name of one of the Tokugawa Shoguns, Tsunayoshi. Here, these are the characters for your name." She took out a pen from her pocket and wrote some Japanese Hiragana on her palm, showing it to the young brunette who squinted his eyes.

綱吉.

"That looks cool, what are those characters?" The now-named Tsuna looked at the two characters in her palm in a child-like awe, making the young matron smile.

"It's called Hiragana, Tsuna. It's a component of Japanese language, alongside kanji and katakana. And..."

Hotaru Mika continued to explain Japanese language and languages in general to a curious Tsuna, who had temporarily forgotten about his circumstances. Outside, by the door, a group of children watched with light hearts, knowing in their hearts, that they'll soon gain another 'family' member.

* * *

 **So Takeshi and Hayato makes an appearance, who do you think will be next? Oh, just to set something straight, in regards to their quirks, it won't necessarily have anything to do with Dying Will Flames or Pyrokinetic like quirks. For example, I've just mentioned that Hayato is quirkless, but has splendid archery skills and is a piano prodigy.**

1) Nana's son (Tsuna) was left in an orphanage in this fic, not foster care. Due to her husband being slain, she didn't want her son to be left to the same fate so she dropped him at the front of an orphanage.

2) Hayato and Takeshi won't be the only ones of Tsuna's Guardians to appear in this fic, and since it's set during All Might's UA years, it should be decades before KHR canon. So think of this as their previous life, if you want to. And I think I had Chrome in the prologue, mentioned anyway.

3) Yes, Hayato is quirkless, try to guess who were some of the other kids who made an appearance here.

4) And since we're on the topic of Hayato, I know he acts a little out of character, like taunting the other boy, being more talkative, emotional and stuff. But hey, he's still a child and he didn't have as bad a childhood as canon Hayato.

5) Just to set the timeline straight, the timeline here was set during All Might's years, so around 55-70 years before the real KHR canon.

6) If anyone reading this also reads my other story The Trinisette Heirs, you'll know that I try to avoid OCs as much as possible. In that story, however, the only OC is a butler named Michaelo, who plays the part of a 'father' to one of the three main protagonists of the story. Same goes to Hotaru Mika here, playing the 'mother' to the children here. I hope that Mika will turn out as well-liked as Michaelo in Trinisette Heirs.


End file.
